In general, one or a pair of doors is mounted at furniture such as sinks, drawers or the like in such a manner as to pivotally rotate about a hinge shaft. A fluid damper is mounted on the inner wall or the front side of the furniture so as to absorb the impact generated in the course of closing the door to minimize noise due to the impact and lengthen the lifespan of the furniture.
That is, as shown in FIG. 1, U.S. Pat. No. 6,802,408 discloses a fluid damper 100 including a cylinder 110 having an oil chamber 115, a piston 120 accommodated in the oil chamber 115 and having a pressurizing bracket 125 provided at the tip thereof, a spring 130 accommodated in the oil chamber 115 and having a guide 135 mounted at a front portion thereof, a linkage bar 140 for interconnecting the pressuring bracket 125 and the guide 135, and a plurality of movable ring disks 145 arranged on the outer circumferential surface of the linkage bar 140.
Thus, when an external force is exerted to the fluid damper 100, three ring disks 145 come into close contact with the bracket 125 while being sequentially bent back to move closer together as much as a pressure corresponding to the external force applied to the piston 120 in the forward direction of the movement of the piston 120, and hence oil in the cylinder 100 flows through oil holes formed in the ring disks 145 and openings 125a formed in the bracket 125 to thereby perform a buffer action.
On the contrary, when the external force exerted to the fluid damper 100 is released, the ring disks 145 return to their original positions by an elastic restoring force of the spring. Then, oil in the cylinder 110 flows through a space formed between the outer circumferential surfaces of the ring disks 145 and the inner wall of the cylinder 110 via the openings 125a of the bracket 125. As a result, the ring disks 145 sealingly block the flow path
However, in the process where the external force exerted to the fluid damper 100 is released and the ring disks 145 return to their original positions, oil is allowed to flow only through the outside of the ring disks 145, i.e., a gap formed between the inner wall of the cylinder 110 and the outer circumferential surfaces of the bracket 125, and hence an increased elastic force of the spring 130 is required to improve the returning force and the buffering force of the piston 120.
For this reason, if the elastic force of the spring 130 in the fluid damper 100 is increased, for example, the fluid damper can be used for a large or heavy door. But, in case of a small or light door, the restoring force of the spring 130 is greatly exerted, and so the door is closed with it widened by a certain aperture angle, resulting in a degradation of the sense of beauty of the outer appearance of the furniture.
Furthermore, the elastic force of the spring 130 is required to be reduced in order to overcome the aforementioned shortcoming of the fluid damper 100 and the cylinder 110 is required to be constructed larger than the bracket 125 in order for the piston 120 to be rapidly returned to its original position. Therefore, there occurs a problem in that a load applied to the fluid damper is not suitably absorbed.
Meanwhile, conventional products such as the fluid damper 100 have been proposed in which a buffer spring is interposed between the piston 120 and the bracket 125 to improve the operation capability of the piston. However, the conventional products entail a problem in that the manufacturing cost and assembling cost of the buffer spring are incurred additionally, thereby increasing the product price.